Study On New Technology Of Stage Grinding And Separation Process In Donganshan Iron Ore

In this paper,process mineralogy characteristics of high-silica low-grade hematite ore from Donganshan was researched in detail.Process mineralogy characteristics of this low-grade hematite ore from Donganshan showed that the total iron grade was 33.28%,mainly existing in the form of hematite and magnetite,Other minerals are mainly quartz,carbonate minerals and chlorite etc.Iron minerals mainly exist in the form of fine hematite,iron minerals and gangue quartz exists in the intergrowth form,difficult to dissociate.Basis on the process mineralogy characteristics of the hematite ore from Donganshan,stage grinding-magnetic separation-reverse flotation experiment was conducted,we systematically examined the effects of grinding size and magnetic field intensity on magnetic separation,flotation reagent system and other factors on the flotation process,the optimum conditions of separation process were determined as follows:the grinding size was-0.074 mm occupying for 80%,the low magnetic field intensity was 103.5KA/m and the high magnetic field intensity was 740KA/m for the first magnetic separation,the grinding size was-0.043 mm occupying for 82%,the low magnetic field intensity was 103.5KA/m and the high magnetic field intensity was 740KA/m for the second magnetic separation.The experiment results of the mixed magnetic concentrate by flotation showed that the TFe grade of 65.32%,recovery of 75.71%products could be obtained after flotation separation at the optimum conditions as follows:the grinding size was-0.038 mm occupying for 95%,the pH of 11.50,the CaO amount of 1000g/t,the starch amount of 1050g/t,the collecting agent amount of 550g/t in roughing flotation,the collecting agent amount of 300g/t in cleaning flotation.Coarse and fine classification-magnetic-reverse flotation experiment was conducted,the magnetic separation process and the reverse flotation process was systematically examined,the optimum conditions of separation process were determined as follows:the 0.074mm circular vibrating screen was used for classification the grinding size was-0.074 xnm occupying for 80%for the first classification process,the grinding size was-0.074 mm occupying for 90%for the second classification process,the low magnetic field intensity was 103.5KA/m and the high magnetic field intensity was 740KA/m for the magnetic separation.The experiment results of the mixed magnetic concentrate by flotation showed that the TFe grade of 64.45%,recovery of 71.65%products could be obtained after flotation separation at the optimum conditions as follows:the grinding size was-0.038 mm occupying for 95%,the pH of 11.50,the CaO amount of 1000g/t,the starch amount of 1100g/t,the collecting agent amount of 600g/t in roughing flotation,the collecting agent amount of 325g/t in cleaning flotation.The particle size distribution,the iron mineral distribution rate and liberation degree of iron and gangue minerals was researched for the magnetic separation products and the flotation process products from magnetic separation and reverse flotation process,to study the reasons for loss of iron minerals in magnetic separation and flotation process.The iron mineral distribution rate was high in the-0.025mm of the tailing from high intensity magnetic separation,this part of the iron minerals was difficult to obtain in magnetic separators effectively.The flotation recovery rate was not high,which becaused the iron minerals of-0.025mm fine particle flotation effect was poor,this particles were easier access to the tailings in the flotation process.The coarse and fine classification-magnetic-reverse flotation lost more finer grained iron minerals than the stage grinding-magnetic separation-reverse flotation,so the latter has better beneficiation index.In this paper,research experiment was carried out for the low-grade hematite ore from Donganshan,The research has the important guiding significance for the production and transformation of the hematite ore in the DongAnshan,and can provide reference for the development and utilization of other iron ore.